It's widely seen as a referendum on the Trump presidency

Millions of Americans go to the polls in midterm elections today, to determine the political make-up of the House and Senate.

The vote is widely seen as a referendum on the presidency of Donald Trump.

Democrats and Republicans agree on one thing: this is one of America's most important mid term elections in decades.

Democrats are hoping Donald Trump's low approval ratings will give them a majority in the House of Representatives.

That would allow them to frustrate the president's ability to get legislation through Congress - and could even allow them to start an impeachment process.

In this file photo, residents vote early at the Douglas County Election Commission office in Omaha, Nebraska | Image: Nati Harnik/AP/Press Association Images

Just one-third of Senate seats are being contested but it's thought unlikely that the Republicans will lose their control of the upper house.

President Trump's been campaigning hard around the country - with accusations he's used racial issues to boost support.

But he's also relying on strong economic growth to get the vote out.

"The first thing they say to me is congratulations Mr President - you have the hottest economic nation anywhere in the world".

Voting begins from midday Irish time, with exit polls giving a picture of the likely result later tonight.